Economy of energy and the valorization of by-products in the food industries are a constant preoccupation. The valorization of these by-products requires pre-concentration treatments; one thereof, reverse osmosis, has been at present developed.
In this process, the liquid to be treated is passed through membranes under pressure. However, some constituents of food by-products have a tendency to precipitate and finally clog up the membranes, which necessitates frequent stoppages of the installation and the replacement of the membranes. Thus, in the milk industry, some constituents of the lactoserum, such as the phosphocalcic compounds, exhibit this tendency to crystallize in the course of the treatment in the reverse osmosis installation. A conventional reverse osmosis installation comprises a system supplying the product to be treated, an optional buffer tank, followed by a force pump termed a low-pressure pump and delivering pressures of between 1 and 10 bar, then a force pump termed a high-pressure pump and whereby it is possible to reach pressures of as much as 100 bar, usually of the order of 50 bar, in the region of the entrance to the reverse osmosis filters, and lastly a tank for storing the concentrate.